1. Field of the Invention
The invention relates to nonwoven articles used for abrasively cleaning surfaces and having antimicrobial properties to prevent the growth of microbes in the nonwoven article during storage after having been used in a wet environment.
2. The State of the Art
Antimicrobial compounds have been used for decades in health care environments, such as in hospitals and physicians' offices, ever since Louis Pasteur's discovery of microbes as communicators of disease and infection. In the typical health care setting, different types of compounds are used to clean and disinfect different surfaces. These compounds can be as varied as the surfaces; everything from floors to tables to countertops made from plastics (e.g., melamine types) or metals (e.g., stainless steel) need to be cleaned.
More recently, antimicrobial compounds have been sold to consumers especially for cleaning kitchen and especially bathroom fixtures (e.g., toilets, sinks, bathtubs and showers). These formulations typically contain a quaternary ammonium compound optionally mixed with a surfactant, detergent, foaming agent, mild abrasive, and the like, and various combinations thereof. Still more recently, the transmission of infections microbes from raw food products, typically raw proteinaceous foodstuffs (typically chicken and beef), has heightened consumer awareness of microbial contamination and the need to cleanse and disinfect food preparation utensils and surfaces. Accordingly, the latest products have been liquid soaps containing an antimicrobial compound; these types of products were formerly available only in hospitals where soaps and surgical gowns had antibacterials incorporated therein. And still more recently childrens' toys, pacifiers, and various apparatus (e.g., playpens, bassinets, etc.) have been available with antibacterial properties so that microorganisms do not grow thereon. See, e.g., Stuart H. Levy, "The Challenge of Antibiotic Resistance," Scientific American (March 1998, p. 46-53).
Concomitant with consumer's awareness of becoming accidentally contaminated from bacteria living on food preparation surfaces, manufacturers and consumers came to realize that items such as sponges and towels (paper or cloth) that are used to clean such surfaces could be microbe-friendly environments because of their relatively high residual water content after use. Besides a food source and a tolerable temperature range, the other main requirement for bacterial growth is water. Sponges and towels absorb water and even when wrung and squeezed, may retain an amount of water sufficient to allow for bacterial growth in their interiors. For example, Roenigk, in U.S. Pat. No. 5,541,233 (the disclosure of which is incorporated herein by reference) describes the use of the combination of a chelating polymer and a metal complex for use in a water absorbing porous article (such as a sponge or towel). Others describe mixtures of compounds, such as a mixture of diazolidinyl urea and iodopropynyl butylcarbamate in T. Elder et al, in Cosmetics and Toiletries, v. 112, n. 8, p. 73 (1997), for use in personal care formulations.
Various types of abrasive cleaning pads have been devised. Winston, in U.S. Pat. No. 3,103,031, describes a non-woven scouring pad having a combination of synthetic fibers (e.g., urethane, epoxy, polyester) and metallic filaments interwoven. Cameron, in U.S. Pat. No. 3,109,191, describes a scouring article comprising a non-woven synthetic fiber bat bound with an adhesive and the fibers then plated with metal. Stein et al., in U.S. Pat. No. 3,324,609, describes an abrasive article having a non-woven web reinforced joined to a coextensive woven web; the non-woven web can be coated with an adhesive containing abrasive particles. Guilbault et al., in U.S. Pat. No. 4,649,079, teaches incorporating a hydrophobic, water in-insoluble biocide into a hydrophobic fiber by passing the fiber through a bath of the biocide. Other patent describing articles and fibers similar to these are described in the following U.S. Pat. No. 2,958,593 to Hoover et al.; U.S. Pat. No. 3,261,675 to Cameron; U.S. Pat. No. 3,280,517 to Copeland; U.S. Pat. No. 4,715,150 to Takeuchi et al.; U.S. Pat. No. 4,781,974 to Bouchette et al; and U.S. Pat. No. 4,801,493 to Ferziger et al.; U.S. Pat. No. 5,152,809 to Mattesky; U.S. Pat. No. 5,626,512 to Palaikis et al.; and U.S. Pat. No. 5,856,002 to Mori. The disclosures of all of these patents are incorporated herein by reference.